Three-dimensional nanoanalysis with the tomographic atom-probe

The tomographic atom-probe is a nanoanalytical instrument which provides three-dimensional maps of chemical heterogeneities in a metallic material on a subnanometric scale. The basic principle of this new generation of apparatus relies on the field evaporation and ionisation of material atoms and the localization of generated ions on a position-sensitive multidetector. Chemical species are identified by time-of-flight mass spectrometry. Local chemical composition in a small selected region of the reconstructed volume (10 x 10 x 1000 nm(3)) may be therefore quantitatively measured. Illustrations of performance of this new generation of apparatus are given (GP zones in Al Cu, precipitation and ordering in two-phase gamma/gamma' NiCrAl single crystal alloys).